CVE-2021-28161Public exploitNetwork attack vector

JavaScript execution via unsanitized debug-console HTML

Published Mar 12, 2021 · Updated Aug 3, 2024

Cross-site scripting in Eclipse Theia 1.8.0 and earlier allows remote attackers to run JavaScript through crafted debug-console output. The ansi-console-item component passes attacker-controlled htmlContent to dangerouslySetInnerHTML without sanitization, causing the frontend to interpret embedded markup and script. A user must start a debugging session that emits the crafted output; execution occurs in the Theia frontend and can read or alter data available to that session.

CVSS severity6.1
Medium
EPSS probability0.71%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Eclipse Theia 1.8.0 and earlier allows remote attackers to run JavaScript through crafted debug-console output. The ansi-console-item component passes attacker-controlled htmlContent to dangerouslySetInnerHTML without sanitization, causing the frontend to interpret embedded markup and script. A user must start a debugging session that emits the crafted output; execution occurs in the Theia frontend and can read or alter data available to that session.

The record

CVE
CVE-2021-28161
Published
Mar 12, 2021
Updated
Aug 3, 2024
Vendor
The Eclipse Foundation
Product
Eclipse Theia
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 12, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <=1.8.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Eclipse Foundation · Eclipse Theiaversion=unspecified <=1.8.0

Published CVSS scores

6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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